Frame assembly for an articulated construction machine

ABSTRACT

In many types of construction machines, the frame assembly comprises a rear frame that supports the engine and the majority of the drive train components and a front frame that supports the work implement and related structure. In this type of machine, the two frames are normally pinned together and the front frame is articulated with respect to the rear frame by a pair of steering cylinders to provide steering for the machine. In order to provide the required structural support for the components of the work implement and to accommodate the steering forces, the front frame is necessarily quite large. The present invention provides a front frame (12) structure that includes a pair of main side plates (62, 64) and a substantially planar support plate (74) that is mounted to a first end portion of the side plates (62, 64). The support plate (74) mounts an axle assembly directly thereto and defines a pair of mounting bores (84) that are positioned, on a rearmost portion of the support plate (74). The bores define a mounting point for the steering cylinders (32) which are mounted between the front and rear frames (12, 14) in an orientation that is substantially in line with the support plate to transmit the forces from the steering cylinders (32) directly into the support plate (74).

This application is a continuation-in-part of Ser. No. 08/679,546 filedJul. 12, 1996, abandoned.

TECHNICAL FIELD

This invention relates to a frame assembly and more particularly to themounting arrangement for the steering cylinders that extend between thefront and rear frame assemblies of an articulated construction machine.

BACKGROUND ART

In the operation of construction machines, it has been found desirableto steer the machine by rotating the front portion of the machine withrespect to the rear portion. In order to do this, it is necessary toprovide two separate frames that are pinned together about a verticalaxis and extend hydraulic cylinders therebetween to obtain the desiredrotation or articulation. Typically, the engine and drive traincomponents are mounted on the rear portion of the machine and the workimplement is mounted on the front portion of the machine.

In the case of some machines, the articulated wheel loader, for example,the front frame portion is subject to extremely high loads from severaldifferent sources. One primary source occurs during the steeringfunction of the vehicle. Since the front axle is mounted to the frontframe, there must be substantial support for it as it steered over allkinds of terrain. The forces applied by the steering cylinder to rotatethe front frame with respect to the rear frame to steer the axle arealso quite large. The support brackets for the steering cylinders arenormally positioned on the sides of the front frame assembly atlocations that are spaced from the axle centerline, through which theforces are transferred. As this spacing increases, so to do the forcespassing therethrough, which ultimately requires exceptionally largesupport brackets for mounting structures.

These factors inherently result in a structure that is quite large inboth height and width. With the increase in size however, come severaldisadvantages. The overall complexity and weight are exceptionallycostly in terms of the numbers of components that must be weldedtogether and the expense of material. Additionally, the operation of themachine is hampered because the large size of the structure can reducethe operators visibility to the work implement. This especially truewith respect to the line of sight to the base and the corners of theimplement.

The present invention is directed to overcoming one or more of theproblems set forth above.

DISCLOSURE OF THE INVENTION

In one aspect of the present invention, a frame assembly is provided foran articulated machine. The articulated machine includes a front framethat has a pair of side plates that have a first and second end portionsand are positioned in spaced parallel relation to one another. A firstsupport plate having a generally planar configuration is secured to thefirst and second side plates at the respective first end portionsthereof. The first support plate has a pair of bores definedtherethrough on opposing side portions thereof. A rear frame portion ispivotally mounted to the front frame portion for relative movement withrespect thereto about a pivot axis. A pair of steering cylinders areinclude that have a first end portion mounted to the rear frame onopposing sides thereof and a second end portion mounted to the firstsupport plate. The cylinders are positioned substantially in line withthe support plate.

With a frame assembly as set forth above, the axle housing is mounted invery close proximity to the support plate. Since the steering cylindersare mounted in line with the support plate, the forces are directlytransferred into the support plate and thereby substantially directlyinto the axle housing as well. This design results in a very direct andefficient transfer of forces between the steering cylinders and the axlehousing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, side view of a portion of a constructionmachine that embodies the principles of the present invention;

FIG. 2 is a diagrammatic side elevational view of the front frameportion of the construction machine shown in FIG. 1;

FIG. 3 is a diagrammatic top view of the frame member shown in FIG. 2;

FIG. 4 is a diagrammatic isometric view of the front frame member asviewed from an elevated position at the forward portion of the machineon the operator's right side; and

FIG. 5 is a diagrammatic isometric view similar to that of FIG. 4 withportions of the frame removed to more clearly view the structure.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, particularly FIG. 1, it can be seen thata construction machine 10 is shown. The machine has a first, or frontframe assembly 12 that is pivotally mounted to a second or rear frameassembly 14. The two frame members define a hitch assembly 16 that hasspaced apart mounting portions 18 and 20 that are pinned together alonga generally vertical axis. The rear frame assembly mounts an engine anda drive train (not shown) that provides motive traction to both a frontand rear axle assembly that are mounted on the respective front and rearframes. A pair of wheels are supported by the each axle assembly andprovide movement of the machine in a well known manner. In addition tosupporting a front axle assembly, shown generally at 26, the front frame12 provides the support for a lift arm assembly 30. The front frame 12is rotatable with respect to the rear frame 14 about the pivotalmounting therebetween by a pair of steering cylinders 32 (one shown)that are mounted on opposite sides of the hitch assembly. Each steeringcylinder has a first end portion 34 mounted to the rear frame and asecond end portion 36 mounted to the front frame in a manner to bedescribed in greater detail hereinafter. Extension and retraction of thesteering cylinders causes the front frame to articulate with respect tothe rear frame to provide steering for the machine.

The lift arm assembly 30 has a first end portion 38 that is pivotallymounted to the front frame 12 and a second end portion 40 that mounts awork implement 42, such as a bucket. The lift arm is moved in agenerally vertical plane by a pair of lift cylinders 44 (one shown) thathave a first end portion 46 pivotally mounted to the front frame 12 anda second end portion 48 pivotally mounted to the lift arm at a locationshown at 50. The work implement 42 is pivotally mounted to the lift armat 52 and is rotatable about the mounting by a tilt arrangement 54 thatis mounted between the lift arm and the work implement. A tilt cylinder56 has a first end portion 58 that is rotatably mounted to the frontframe 12 and a second end portion 60 that is connected to the tiltarrangement 54. Rotation of the implement about its mounting occurs as aresult of the extension and retraction of the tilt cylinder.

Turning now to FIGS. 2-5, the front frame 12 assembly can be seen ingreater detail. The front frame assembly 12 is defined by a plurality ofmain structural members as well as a plurality of subassemblies thatprovide support for or accommodate loading from the various hydrauliccylinders or other components attached to the frame assembly.

The main structural components of the front frame assembly include apair of main sides plates 62 and 64 that are generally oriented in alongitudinal direction with respect to a centerline of the machine, andare spaced from one another a preselected width W (FIG. 3). The width Wis sufficient to receive the first end portion 38 of the lift armassembly 30 therebetween.

A cast tubular member 66 extends between the side plates 62 and 64 andis received in bores 68 and 70 that are formed in the respective sidesplates 62 and 64 along a common axis X. The tubular member 66 is fixedto the side plates by welding. The tubular member is sufficient toreceive a pin assembly 72 that pivotally mounts the first end portions46 of the lift cylinders 44 at a location that is outwardly adjacenteach of the main side plates.

A first main support plate 74 is transversely positioned with respect tothe side plates 62 and 64 and is secured thereto at a first or forwardlyextending end portion 76 and 78 of each main side plate, to lie in agenerally horizontal plane. The first main support plate 74 issubstantially planar and engages the lower edge defined by the forwardend portions of the sides plates and extends laterally beyond each sideplate to define a wing 80 and 82 on opposing sides of the side plates 62and 64. The first main support plate defines a pair of bores 84 at arearmost portion thereof, that extend through the first main plate. Thebores 84 are adapted for receiving a pin assembly utilized to mount thesecond end portion 36 of one of the steering cylinders 32.

A second main support plate 86 is positioned between and is connected tothe main side plates 62 and 64 and has a first end portion 88 that isaffixed to the first main support plate 74 and a second end portion 90that is secured to a tilt tower assembly 92 that will be described ingreater detail hereinafter. The majority of the second main supportplate 86 is positioned at an angle to the first main support plate andextends upwardly toward the rear portion of the frame assembly 12. Thefirst end portion 88 of the second main support plate 86 is angled orcurved downwardly and defines a vertically extending wall 94 that has apreselected height H that intersects with the angled portion of thesecond main support plate.

A plurality of reinforcing members in the form of spreader plates orgussets 96, 98, and 100 are positioned internally between the main sideplates 62 and 64. As can best be seen in FIG. 5, each gusset plate issecured to the respective side plates, the first, transverselyextending, main support plate 74 and at least a portion thereof issecured to the angled, second main support plate 86. The gussets arelongitudinally spaced from one another along the forward portion of theframe assembly. A plurality of outer gussets, all of which are indicatedby reference numeral 102, are positioned on each of the wings 80 and 82defined by the first main support plate 74 and are aligned with theinternally positioned gussets 96, 98 and 100. A plurality of mountingholes 108 are formed in the first main support plate 74 on the forwardportion thereof in the area of the spreader plates and gussets. Themounting holes 108 receive suitable fasteners (not shown) that mount thefront axle assembly directly to the first main support plate 74. Thespreader plates and gussets provide substantial torsional support forthe forward portion of the frame assembly 12 to accommodate the loadingapplied by the axle assembly as the machine is operated.

A hitch assembly 114 is defined on a second or rearwardly directed endportion 116 of the front frame assembly 12. A first, or upper hitchplate 118 extends transversely between the main side plates 62 and 64and is fixedly secured thereto by welding for example. A second, orlower hitch plate 120 is also has at least a portion thereof positionedbetween the main side plates and is also welded thereto at a lowerextremity of the frame assembly 12 at a vertically spaced location fromthe upper hitch plate 118. Each hitch plate 118 and 120 defines a bore122 and 124 respectfully, that are aligned with one another on thevertical pivot axis Z about which the front and rear machine framesarticulate. A first hitch support plate 128 extends between the upperand lower hitch plates 118 and 120 and is transversely positionedbetween the main side plates 62 and 64. The hitch support plate 128 issecured to both hitch plates at its upper and lower ends and as well asboth side plates. A second hitch support plate 130 extends between thefirst hitch support plate 128 and the tubular member 66. The secondhitch support plate 130 is generally horizontally oriented and has afirst end portion 132 that is attached to the first hitch support plate128 at the approximate midportion thereof and a second end portion 134that is slightly curved upwardly to engage the tubular member 66 at anangle that will intersect the axis X defined by the tubular member 66.The second hitch support plate 130 is positioned adjacent an opening 136in each of the main side plates 62 and 64 and provides a supportplatform for various machine components, such as hydraulic valvesutilized in the operation of the tilt and lift cylinders, in an areathat is accessible for service. A pair of openings 138 and 140 aredefined in the first hitch support plate 128 above and below the secondhitch support plate 130 for the same purpose.

A tilt tower arrangement, shown generally at 92 is positioned betweenand secured to the main side plates 62 and 64. The tilt towerarrangement includes a pair of generally vertically oriented mountingplates 144 and 146 that are transversely spaced from one another adistance sufficient to receive the tilt cylinder 56. The mounting plates144 and 146 define bores 148 and 150 that are aligned along a commonaxis Y and receive a pin assembly 152 (FIG. 1) that pivotally mounts thefirst end portion 58 of the tilt cylinder 56. The mounting plates 144and 146 are mounted to a generally vertical, first tilt tower supportplate 154 that is positioned transversely between the side plates 62 and64 on the rear side of the mounting plates 144 and 146. A first or lowerend portion 156 of the first tilt tower support plate 154 is welded tothe respective side plates 62 and 64 and the upper hitch plate 118. Asecond tilt tower support plate 158 is portioned between and is affixedto the side plates 62 and 64. The second tilt tower support plate 158has a first end portion 160 that is secured to the first tilt towersupport plate 154 and a second end portion 162 that is secured to thetubular member 66. The first end portion 160 is curved and serves as abase plate for the mounting plates 144 and 146. The second end portion162 is generally planar and is positioned to extend at an angle thatsubstantially intersects with the axes X and Y that are respectivelydefined by the tubular member 66 and the bores 148 and 150 defined bythe mounting plates 144 and 146 respectively. The second end portion 162engages and is secured to the second end portion 90 of the second, orangled main support plate 86. A pair of support plates, one of which isshown at 164, is provided for each of the mounting plates 144 and 146respectively. Each support plate 164 and 166 is vertically aligned withone of the mounting plates and is mounted to both the first and secondtilt tower support plates 154 and 158 along two surfaces thereof.Because the mounting plates and support plates are aligned on opposingsides of the second tower support plate, it is to be understood thatthey could be one continuous plate without departing from the invention.However, for manufacturing purposes, it is beneficial to separate theminto two individual plates positioned as described.

Torsional support for the tilt tower arrangement 142 is provided by apair of upper and lower plates 168 and 170 that extend between the upperhitch plate 118 and second tower support plate 158. The upper and lowerplates 168 and 170 are spaced from one another a distance that isapproximately the height of the upper hitch plate 118 and define abox-shaped configuration to provide torsional stiffness to this area ofthe front frame 12. While not clearly shown, the lower plate 170includes a portion that is positioned between the support plates 164 and166. This portion of the lower plate may be a separate plate that may ormay not be aligned with the lower plate 170.

Industrial Applicability

The frame assembly 12 set forth above, mounts a lift arm assembly thatmay be positioned between the main side plates 62 and 64. In doing sothe overall width of the frame assembly may be much narrower that priorframe assemblies. Also, the vertical height of the frame assembly at theforward end is also greatly reduced because of the second or angled mainsupport plate 86. In fact the vertical height H established by theangled main support plate may fall within a range of 0.2 to 0.6 of thepreselected width established by the side plates 62 and 64. These twophysical components provide an operator exceptional visibility to theimplement both down the center of the machine as well as to the cornersof the work implement.

In addition, the load transfer between the front and rear frames 12 and14 respectively, is extremely efficient. This is especially true withthe mounting of the steering cylinders 32. Actuation of the steeringcylinders will cause the front frame to articulate about the verticalaxis A to steer the machine. This can be the source of extreme loading.The steering cylinders are mounted directly to the first main supportplate 74 and are essentially positioned in line with it. This lineartransfer of forces eliminates the need for substantial support bracketsthereby reducing weight and cost both in components and manufacturingand assembly.

The hitch assembly 114 is another source of great loading. The subjectinvention utilizes a single upper and lower hitch plate 118 and 120respectively, that are interconnected by a continuous first hitchsupport plate 128. The first hitch support plate is secured on allsides. The upper and lower extremities are welded to the upper and lowerhitch plates and the opposing side portions are welded to each sideplate 62 and 64. Prior designs have not utilized continuous plates inthis manner and have used extensive box sections to provide the requiredsupport for the upper and lower hitch plates.

With the frame assembly set forth above, it can be seen that a maximumof structural integrity is obtained with a relatively few components.The positioning of the various plates provides extremely efficient loadtransfer allows the overall structure to be reduced in size. With thereduction in size, the overall visibility to the forward portion of themachine is greatly increased which will result in an increase in machineperformance and productivity. The reduction in size and components alsoresults in a reduction in manufacturing costs since the structure ismore easily fabricated.

Other aspects, objects and advantages of this invention can be obtainedfrom a study of the drawings, the disclosure and the appended claims.

We claim:
 1. A frame assembly, comprising:a front frame (12) having pair of side plates (62,64) having first (76,78) and second end portions (116) and being positioned in spaced parallel relation to one another and a first support plate (74) having a generally planar configuration and being secured to the first and second side plates (62,64) at the respective first end portions thereof (76,78), said first support plate (74) having a pair of bores (84) defined therethrough on opposing side portions thereof; an axle assembly (26) mounted to the first support plate (74) in subjacent relation thereto; a rear frame portion (14) pivotally mounted to the front frame portion (12) for relative movement with respect thereto about a pivot axis (Z); and a pair of steering cylinders (32) having a first end portion (34) mounted to the rear frame (14) on opposing sides thereof and a second end portion (36) mounted to the first support plate (74), said cylinders (32) being positioned substantially in-line with the first support plate (74).
 2. The frame assembly (12) as set forth in claim 1 wherein the first support plate (74) is secured to a lower edge portion of each side plate (62,64) in a manner to extend laterally outwardly of each side plate (62,64) to define a wing member (80,82) on opposite sides of each side plate (62,64).
 3. The frame assembly (12) as set forth in claim 2 wherein a plurality of reinforcing plates (96,98,100) are positioned between and secured to the side plates (62,64) and the first support plate (74) in the vicinity of the mounting between the axle assembly (20) and the support plate (74).
 4. The frame assembly (12) as set forth in claim 2 wherein the bores (84) defined in the first support plate (74) are positioned on the respective wing members (80,82). 